Field of the Invention
The present invention relates to a structure and a paint for forming a surface coat layer.
Discussion of the Background
A catalytic converter is provided in the path of an exhaust pipe to treat toxic substances contained in exhaust gas discharged from an engine.
It is necessary to maintain the temperatures of exhaust gas, an exhaust pipe through which the exhaust gas passes, and the like at temperatures suitable for catalytic activation (hereinafter, also referred to as catalyst activation temperatures) in order to improve conversion efficiency of toxic substances by a catalytic converter.
In a conventional exhaust gas purifying system, the temperature of the catalytic converter at the start of the engine is lower than the catalyst activation temperature, and thus the catalyst fails to provide its functions. It has therefore been difficult to completely prevent toxic substances from being discharged at the start of the engine.
For this reason, it is required to raise the temperature of an exhaust pipe connected to an engine to the catalyst activation temperature in a short time after the start of the engine.
JP 2008-69383 A, JP 2009-133213 A, and JP 2009-133214 A each deal with the above problem by providing a structure that includes a base made of a metal and an inorganic material surface layer made of crystalline and amorphous inorganic materials. The inorganic material surface layer has lower heat conductivity than the base but has a higher infrared radiation rate than the base.